There are a growing number of devices which require portable power sources. A variety of different types of portable power sources are available.
One of these types of portable power sources is batteries. For most applications batteries provide an adequate source of power. Unfortunately, batteries have finite lifetime and thus require periodic replacement.
Another type of portable power source are solar powered systems. Solar power systems also provide an adequate amount of power and provide a recharging mechanism. Unfortunately, the recharging mechanism requires solar radiation, which may not always be available and requires proper orientation to the solar radiation, which may not always be convenient.